upsertArtistSimilar keeps the existing matched path (top-K rows into
artist_similarity) and adds a parallel unmatched-persist loop with the
same top-K cap. Empty-name rows are skipped — we can't render a
suggestion card without a name. Logs unmatched-side errors at WARN
without aborting the tick (mirrors the matched-path policy).
Replace stub with full tickOnce: drains played tracks/artists via
ListPlayedTracksNeedingSimilarity / ListPlayedArtistsNeedingSimilarity,
calls LB SimilarRecordings/SimilarArtists, filters to local library via
bulk MBID lookup, enforces top-K=20 by score, and upserts similarity
rows. 429 aborts the entire tick; other errors log-and-skip. Ten
integration tests covering no-op, library filtering, top-K cap, 7-day
freshness cap, stale refresh, 429 abort, transient skip, and artist
pass.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
bvandeusen